1. Field of the Invention
The present invention relates to an apparatus and a method for generating air pressure in an eco-friendly vehicle; and, particularly, to an apparatus and a method for generating air pressure in an eco-friendly vehicle that is configured to allow an engine driven air compressor and an electric air compressor to be optionally or alternately operated depending on a traveling state of a vehicle and whether or not a voltage system is operating normally in an eco-friendly vehicle equipped with an engine and a high voltage battery.
2. Description of Related Art
Often times a vehicle, particularly a commercial vehicle such as a bus, a truck, or a special purpose vehicle, is mounted with an air compressor which is operated by an engine, to provide air pressure required for operation of additional auxiliary devices in the vehicle.
In the vehicle driven by an engine as described above, since the engine is always driven during traveling of the vehicle, the air compressor can only be operated when the engine is currently being operated. In recent years, however, eco-friendly vehicles have begun to emerge in which the engine is not always running, such as a hybrid vehicle. In hybrid vehicles, the vehicle is provided power from both an engine and an electric motor.
As more and more research is conducted on hybrid vehicles, the running time of the engine continually decreases whereas operating time of the motor increases, due to development in technologies for a battery and charging thereof. Also, given the development of plug-in hybrid vehicles, vehicles are becoming even less dependent upon the engine to provide a drive force. Accordingly, a phenomenon has occurred in which air pressure which is required by a variety of devices of the vehicle has decreased due to reductions in operating times of an engine.
Since a decrease of air pressure causes limitations on operations of a variety of special devices including the brakes and the suspension, which are necessary component in order to operate the vehicle, the engine is often operated merely to provide air pressure to these components even when operation of the motor alone would suffice.
Such a problem is also an issue even in an RE-EV (Range Extended Electric Vehicle) equipped with a charging-dedicated engine to increase a traveling range while being operated by electric power charged to mainly a high voltage battery among electric vehicles, besides the hybrid vehicle.